Most computing systems can receive input from a user via an input device such as a mouse. The mouse can allow the user to move an input pointer, e.g., a cursor, in a user interface (UI) on a display screen of the computing system and to make a selection in the UI with the pointer, thereby triggering various operations in the computing system. The mouse can include a mechanism for tracking its motion, which can be translated into signals that the computing system can use to move the input pointer in the UI. For example, an optical mouse can include a small light-emitting diode (LED), located on the underside of the mouse, to bounce light off a surface back to an optical sensor in the mouse in order to track the mouse motion. The optical sensor can send an image of “bounced-back” light to a processor in the mouse, which can determine how far the mouse has moved since the last image. The mouse processor can send the corresponding motion coordinates to the computing system. The motion of the mouse can generally correspond to the motion of the input pointer in the UI. Thus, by moving the mouse on a surface, the user can move the input pointer in similar directions in the UI. In an alternate example, a mouse trackball may be used to track the mouse motion.
The mouse can also include a mechanism for data selection in the UI. The mouse can allow the user to make a selection in the UI on the display screen by moving the pointer. For example, a touch sensitive mouse can include a touch sensor panel, which can include a panel of touch sensors and a touch sensitive surface covering a portion or substantially all of the top surface of the mouse, to make a selection. The touch sensor panel can detect a touch event and the surface location of the touch event using the touch sensors and can send the touch event information to the computing system. The computing system can interpret the touch event and thereafter perform one or more operations based on the touch event. By way of example, a data selection operation, such as a scroll operation, can be performed when a scroll motion is detected on the touch sensitive surface of the mouse. In an alternate example, a mouse scroll wheel may be used to make a selection in the UI on the display screen.
However, when moving the mouse in order to move the input pointer in the UI, it can be difficult for the user to avoid making certain finger motions on the mouse surface, which can be erroneously interpreted as an intended gesture, e.g., a scroll gesture. Conversely, when making certain robust gestures on the mouse surface, e.g., a rotate gesture, in order to cause the computing system to perform an operation, it can be difficult for the user to avoid moving the mouse, which can be erroneously interpreted as an intended mouse motion.